Predicting Amputee Walking Gait Using Ideas from Underactuated Robot
Speaker: Anne Martin Ph.D. Candidate Aerospace, Mechanical Engineering University of Notre Dame
Abstract: Because prostheses do not completely replicate the function of the physiological foot and ankle, amputee gait is both less symmetric and less efficient than normal human gait, which reduces the quality of life of the amputee. By optimizing both the design of prostheses and the amputee’s gait, it is likely that the amputee’s quality of life can be increased. To date, experimental studies of amputee gait, particularly those investigating the effects of prosthesis design, have not yielded convincing results. Predictive modeling studies could provide some much needed quantitative results. Unfortunately, existing models are either too computationally expensive or too simplistic to be used for this purpose.
This talk presents a model of intermediate complexity based on the Hybrid Zero Dynamics (HZD) control approach originally developed for point-foot, underactuated robots. By incorporating feet into the model and correctly choosing the objective function for gait optimizations, the HZD-based model can be extended to accurately predict the lower-limb kinematics and energy expenditure of healthy human walking across a wide range of speeds. The inclusion of feet in the model requires new derivations of the stability and periodicity conditions. To use the model to investigate amputee gait, it must be further extended to allow asymmetrical gait. This talk will describe the model, discuss the technical details of its extension from the original robotic formulation, demonstrate its predictive capabilities for healthy human walking gait via the results of a validation study using existing human data, and present ongoing work in quantifying the trade-off between symmetric and efficient amputee gait. This talk will also discuss how robotic modeling and controls techniques can be used to address health care problems, particularly gait-related problems.
Bio: Anne Martin is a Ph.D. candidate in the Department of Aerospace and Mechanical Engineering at the University of Notre Dame. In 2005, she graduated Summa Cum Laude from the University of Delaware with a bachelor’s degree in mechanical engineering. Her research interests include modeling human gait, particularly impaired human gait, and using such models to develop clinically useful interventions. Her teaching interests lie within the areas of statics, dynamics and controls. Regardless of the course, she is committed to teaching the material in a high-quality, engaging manner. She is a member of the American Society of Biomechanics and ASME.